Hitherto, many vehicles, particularly land vehicles, have been provided with seats convertible into berths but exhibiting several disadvantages; first of all, almost in all cases, there exists an open space between the seat back and the seat itself when the seat is in position for forming a berth.
The seat as well as its back have, usually, a transverse contour provided for supporting the user sideways when the vehicle is moving, but this contour makes the seat quite uncomfortable when used as a berth.
This disadvantage is all the greater when the seat, positioned as a berth, is used in its transverse direction, as is the case in some leisure vehicles, particularly in camping vehicles, where it is expected to use the front seat, in combination with intermediate cushions, for forming a berth the longitudinal direction of which is perpendicular to the vehicle longitudinal axis.